1 /*
   2  * Copyright (c) 2001, 2017, 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 4416800
  27  * @summary Checks that ImageInputStreamImpl.readBit and readBits handle the bit
  28  *          offset correctly
  29  */
  30 
  31 import java.io.ByteArrayInputStream;
  32 import java.io.IOException;
  33 import java.io.InputStream;
  34 
  35 import javax.imageio.stream.FileCacheImageInputStream;
  36 import javax.imageio.stream.ImageInputStream;
  37 
  38 public class ReadBitsTest {
  39     public static void main(String[] args) throws IOException {
  40         byte[] buffer = new byte[] {(byte)169, (byte)85}; // 10101001 01010101
  41         InputStream ins = new ByteArrayInputStream(buffer);
  42         ImageInputStream in = new FileCacheImageInputStream(ins,null);
  43 
  44         if (in.getBitOffset() != 0) {
  45             throw new RuntimeException("Initial bit offset != 0!");
  46         }
  47 
  48         int bit0 = in.readBit(); // 1
  49         if (bit0 != 1) {
  50             throw new RuntimeException("First bit != 1");
  51         }
  52         if (in.getBitOffset() != 1) {
  53             throw new RuntimeException("Second bit offset != 1");
  54         }
  55 
  56         long bits1 = in.readBits(5); // 01010 = 10
  57         if (bits1 != 10) {
  58             throw new RuntimeException("Bits 1-5 != 10 (= " + bits1 + ")");
  59         }
  60         if (in.getBitOffset() != 6) {
  61             throw new RuntimeException("Third bit offset != 6");
  62         }
  63 
  64         int bit1 = in.readBit(); // 0
  65         if (bit1 != 0) {
  66             throw new RuntimeException("Bit 6 != 0");
  67         }
  68         if (in.getBitOffset() != 7) {
  69             throw new RuntimeException("Third bit offset != 7");
  70         }
  71 
  72         long bits2 = in.readBits(8); // 10101010 = 170
  73         if (bits2 != 170) {
  74             throw new RuntimeException("Bits 7-14 != 170 (= " + bits2 + ")");
  75         }
  76         if (in.getBitOffset() != 7) {
  77             throw new RuntimeException("Fourth bit offset != 7");
  78         }
  79 
  80         int bit2 = in.readBit(); // 1
  81         if (bit2 != 1) {
  82             throw new RuntimeException("Bit 15 != 1");
  83         }
  84         if (in.getBitOffset() != 0) {
  85             throw new RuntimeException("Fifth bit offset != 0");
  86         }
  87 
  88         in.close();
  89     }
  90 }