LocalVariableInfo.java :  » Development » javaguard » net » sf » javaguard » classfile » Java Open Source

/**
 * JavaGuard -- an obfuscation package for Java classfiles.
 *
 * Copyright (c) 1999 Mark Welsh (markw@retrologic.com)
 * Copyright (c) 2002 Thorsten Heit (theit@gmx.de)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * The author may be contacted at theit@gmx.de.
 *
 *
 * $Id: LocalVariableInfo.java,v 1.2 2002/05/08 11:53:42 glurk Exp $
 */
package net.sf.javaguard.classfile;

import java.io.*;


/** Representation of a local variable table entry.
 *
 * @author <a href="mailto:theit@gmx.de">Thorsten Heit</a>
 * @author <a href="mailto:markw@retrologic.com">Mark Welsh</a>
 */
public class LocalVariableInfo {
  /** Start of the Program Counter (PC). */
  private int startPc;
  /** The length. */
  private int length;
  /** Name index into the constant pool. */
  private int nameIndex;
  /** Descriptor index into the constant pool. */
  private int descriptorIndex;
  /** Index into the constant pool. */
  private int index;
  
  
  
  
  /** Creates a new LocalVariableInfo object from the given input stream.
   * @param din the input stream
   * @return the LocalVariableInfo object created from the input stream
   * @throws IOException if an I/O error occurs
   */
  public static LocalVariableInfo create(DataInput din)
  throws IOException {
    LocalVariableInfo lvi = new LocalVariableInfo();
    lvi.read(din);
    return lvi;
  }
  
  
  
  
  /** Private constructor that creates a new LocalVariableInfo object.
   */
  private LocalVariableInfo() {
  }
  
  
  
  /** Sets the address of the program counter.
   * @param pc the address of the program counter
   * @see #getStartPc
   */
  protected void setStartPc(int pc) {
    this.startPc = pc;
  }
  
  
  /** Returns the address of the program counter.
   * @return address of the program counter
   * @see #setStartPc
   */
  protected int getStartPc() {
    return startPc;
  }
  
  
  
  
  /**  Sets the length.
   * @param len the length
   * @see #getLength
   */
  protected void setLength(int len) {
    this.length = len;
  }
  
  
  /** Returns the length.
   * @return length
   * @see #setLength
   */
  protected int getLength() {
    return length;
  }
  
  
  
  
  /** Set the name index.
   * @param index index into the constant pool
   * @see #getNameIndex
   */
  protected void setNameIndex(int index) {
    nameIndex = index;
  }
  
  
  /** Return the name index into the constant pool.
   * @return index into the constant pool
   * @see #setNameIndex
   */
  protected int getNameIndex() {
    return nameIndex;
  }
  
  
  
  
  /** Set the descriptor index.
   * @param index index into the constant pool
   * @see #getDescriptorIndex
   */
  protected void setDescriptorIndex(int index) {
    descriptorIndex = index;
  }
  
  
  /** Return the descriptor index into constant pool.
   * @return index into the constant pool
   * @see #setDescriptorIndex
   */
  protected int getDescriptorIndex() {
    return descriptorIndex;
  }
  
  
  
  /** Set the index.
   * @param index index into the constant pool
   * @see #getIndex
   */
  protected void setIndex(int index) {
    this.index = index;
  }
  
  
  /** Return the index into the constant pool.
   * @return index into the constant pool
   * @see #setIndex
   */
  protected int getIndex() {
    return index;
  }
  
  
  
  
  /** Check for Utf8 references to constant pool and mark them.
   * @param pool the constant pool the element belongs to
   */
  protected void markUtf8Refs(ConstantPool pool) {
    pool.incRefCount(getNameIndex());
    pool.incRefCount(getDescriptorIndex());
  }
  
  
  
  
  /** Read the data following the header.
   * @param din the input stream
   * @throws IOException if an I/O error occurs
   */
  private void read(DataInput din)
  throws IOException {
    setStartPc(din.readUnsignedShort());
    setLength(din.readUnsignedShort());
    setNameIndex(din.readUnsignedShort());
    setDescriptorIndex(din.readUnsignedShort());
    setIndex(din.readUnsignedShort());
  }
  
  
  /** Export data following the header to a DataOutput stream.
   * @param dout the output stream
   * @throws IOException if an I/O error occurs
   */
  public void write(DataOutput dout)
  throws IOException {
    dout.writeShort(getStartPc());
    dout.writeShort(getLength());
    dout.writeShort(getNameIndex());
    dout.writeShort(getDescriptorIndex());
    dout.writeShort(getIndex());
  }
  
  
  
  
  /** Dump the content of the entry to the specified file (used for debugging).
   * @param pw the print writer
   * @param cf the class file the element belongs to
   */
  public void dump(PrintWriter pw, ClassFile cf) {
    pw.print("StartPC:          ");
    pw.println(getStartPc());
    pw.print("Length:           ");
    pw.println(getLength());
    pw.print("Name index:       ");
    pw.println(getNameIndex());
    pw.print("Descriptor index: ");
    pw.println(getDescriptorIndex());
    pw.print("Index:            ");
    pw.println(getIndex());
  }
}