1 /*
   2  * Copyright (c) 2010, 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 /* @test
  26  * @bug 6720170
  27  * @summary check for ByteArrayInputStream.skip
  28  */
  29 
  30 import java.io.*;
  31 
  32 public class Skip {
  33     private static void dotest(InputStream in, int curpos, long total,
  34                                long toskip, long expected)
  35         throws Exception
  36     {
  37         System.err.println("\nCurrently at pos = " + curpos +
  38                            "\nTotal bytes in the stream = " + total +
  39                            "\nNumber of bytes to skip = " + toskip +
  40                            "\nNumber of bytes that should be skipped = " +
  41                            expected);
  42 
  43         // position to curpos; EOF if negative
  44         in.reset();
  45         int avail = curpos >= 0 ? curpos : in.available();
  46         long n = in.skip(avail);
  47         if (n != avail) {
  48             throw new RuntimeException("Unexpected number of bytes skipped = " + n);
  49         }
  50 
  51         long skipped = in.skip(toskip);
  52         System.err.println("actual number skipped: "+ skipped);
  53 
  54         if (skipped != expected) {
  55             throw new RuntimeException("Unexpected number of bytes skipped = " + skipped);
  56         }
  57     }
  58 
  59     public static void main(String argv[]) throws Exception {
  60         int total = 1024;
  61         ByteArrayInputStream in = new ByteArrayInputStream(new byte[total]);
  62 
  63         /* test for skip */
  64         dotest(in,  0, total, 23, 23);
  65         dotest(in,  10, total, 23, 23);
  66 
  67         /* test for negative skip */
  68         dotest(in,  0, total, -23,  0);
  69 
  70         /* check for skip after EOF */
  71         dotest(in, -1, total,  20,  0);
  72 
  73         /* check for skip beyond EOF starting from before EOF */
  74         dotest(in,  0, total, total+20, total);
  75 
  76         /* check for skip if the pos + toskip causes integer overflow */
  77         dotest(in, 10, total, Long.MAX_VALUE, total-10);
  78     }
  79 }