1 /*

     2  * Copyright 1998 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 1.1 98/01/12

    26  * @bug 4022294

    27  * @summary Test bufferedinputstream for data loss during skip

    28  *

    29  */

    30 

    31 import java.io.*;

    32 import java.util.*;

    33 

    34 /**

    35  * This class tests to see if bufferinputstream can be reset

    36  * to recover data that was skipped over when the buffer did

    37  * not contain all the bytes to be skipped

    38  */

    39 public class SkipTest {

    40 

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

    42         long skipped = 0;

    43 

    44         // Create a tiny buffered stream so it can be easily

    45         // set up to contain only some of the bytes to skip

    46         DataSupplier source = new DataSupplier();

    47         BufferedInputStream in = new BufferedInputStream(source, 4);

    48 

    49         // Set up data to be skipped and recovered

    50         // the skip must be longer than the buffer size

    51         in.mark(30);

    52         while (skipped < 15) {

    53             skipped += in.skip(15-skipped);

    54         }

    55         int nextint = in.read();

    56         in.reset();

    57 

    58         // Resume reading and see if data was lost

    59         nextint = in.read();

    60 

    61         if (nextint != 'a')

    62             throw new RuntimeException("BufferedInputStream skip lost data");

    63     }

    64 }

    65 

    66 

    67 class DataSupplier extends InputStream {

    68 

    69     private int aposition=0;

    70 

    71     public int read() {

    72         return 'x';

    73     }

    74 

    75     public long skip(long n) {

    76         aposition += (int) n;

    77         return n;

    78     }

    79 

    80     public static final byte[] buffer = {(byte)'a',(byte)'b',(byte)'c',

    81 (byte)'d',(byte)'e',(byte)'f',(byte)'g',(byte)'h',(byte)'i',

    82 (byte)'j',(byte)'k',(byte)'l',(byte)'m',(byte)'n',(byte)'o',

    83 (byte)'p',(byte)'q',(byte)'r',(byte)'s',(byte)'t',(byte)'u',

    84 (byte)'v',(byte)'w',(byte)'x',(byte)'y',(byte)'z'

    85                                          };

    86 

    87     public int read(byte b[]) throws IOException {

    88         return read(b, 0, b.length);

    89     }

    90 

    91     public int read(byte b[], int off, int len) throws IOException {

    92         if (len > buffer.length) len = buffer.length;

    93         System.arraycopy(buffer, aposition, b, off, len);

    94         return len;

    95     }

    96 

    97 }