1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.bcel.util;
18
19 import java.io.ByteArrayInputStream;
20 import java.io.DataInputStream;
21
22 /**
23 * Utility class that implements a sequence of bytes which can be read via the 'readByte()' method. This is used to
24 * implement a wrapper for the Java byte code stream to gain some more readability.
25 */
26 public final class ByteSequence extends DataInputStream {
27
28 private static final class ByteArrayStream extends ByteArrayInputStream {
29
30 ByteArrayStream(final byte[] bytes) {
31 super(bytes);
32 }
33
34 int getPosition() {
35 // pos is protected in ByteArrayInputStream
36 return pos;
37 }
38
39 void unreadByte() {
40 if (pos > 0) {
41 pos--;
42 }
43 }
44 }
45
46 private final ByteArrayStream byteStream;
47
48 public ByteSequence(final byte[] bytes) {
49 super(new ByteArrayStream(bytes));
50 byteStream = (ByteArrayStream) in;
51 }
52
53 public int getIndex() {
54 return byteStream.getPosition();
55 }
56
57 void unreadByte() {
58 byteStream.unreadByte();
59 }
60 }