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 025 * via the `readByte()' method. This is used to implement a wrapper for the 026 * Java byte code stream to gain some more readability. 027 * 028 */ 029public final class ByteSequence extends DataInputStream { 030 031 private final ByteArrayStream byteStream; 032 033 034 public ByteSequence(final byte[] bytes) { 035 super(new ByteArrayStream(bytes)); 036 byteStream = (ByteArrayStream) in; 037 } 038 039 040 public int getIndex() { 041 return byteStream.getPosition(); 042 } 043 044 045 void unreadByte() { 046 byteStream.unreadByte(); 047 } 048 049 private static final class ByteArrayStream extends ByteArrayInputStream { 050 051 ByteArrayStream(final byte[] bytes) { 052 super(bytes); 053 } 054 055 int getPosition() { 056 // pos is protected in ByteArrayInputStream 057 return pos; 058 } 059 060 void unreadByte() { 061 if (pos > 0) { 062 pos--; 063 } 064 } 065 } 066}