001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.util; 019 020import java.io.ByteArrayInputStream; 021import java.io.DataInputStream; 022 023/** 024 * Utility class that implements a sequence of bytes which can be read via the `readByte()' method. This is used to 025 * implement a wrapper for the Java byte code stream to gain some more readability. 026 * 027 */ 028public final class ByteSequence extends DataInputStream { 029 030 private static final class ByteArrayStream extends ByteArrayInputStream { 031 032 ByteArrayStream(final byte[] bytes) { 033 super(bytes); 034 } 035 036 int getPosition() { 037 // pos is protected in ByteArrayInputStream 038 return pos; 039 } 040 041 void unreadByte() { 042 if (pos > 0) { 043 pos--; 044 } 045 } 046 } 047 048 private final ByteArrayStream byteStream; 049 050 public ByteSequence(final byte[] bytes) { 051 super(new ByteArrayStream(bytes)); 052 byteStream = (ByteArrayStream) in; 053 } 054 055 public int getIndex() { 056 return byteStream.getPosition(); 057 } 058 059 void unreadByte() { 060 byteStream.unreadByte(); 061 } 062}