bytesequence.java

该开源工具主要用于class文件的操作

package org.apache.bcel.util;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
import java.io.*;

/**
 * Utility class that implements a sequence of bytes which can be read
 * via the `readByte()' method. This is used to implement a wrapper for the 
 * Java byte code stream to gain some more readability.
 *
 * @version $Id: ByteSequence.java,v 1.1.1.1 2001/10/29 20:00:28 jvanzyl Exp $
 * @author  <A HREF="mailto:[e-mail]">M. Dahm</A>
 */
public final class ByteSequence extends DataInputStream {
  private ByteArrayStream byte_stream;

  public ByteSequence(byte[] bytes) { 
    super(new ByteArrayStream(bytes));
    byte_stream = (ByteArrayStream)in;
  }

  public final int getIndex()   { return byte_stream.getPosition(); }    
  final  void      unreadByte() { byte_stream.unreadByte(); }

  private static final class ByteArrayStream extends ByteArrayInputStream {
    ByteArrayStream(byte[] bytes) { super(bytes); }
    final int  getPosition() { return pos; } // is protected in ByteArrayInputStream
    final void unreadByte()  { if(pos > 0) pos--; }
  }
}