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package com.sun.org.apache.bcel.internal.classfile;

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 * information on the Apache Software Foundation, please see

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import  com.sun.org.apache.bcel.internal.Constants;

import  java.io.*;

/**

 * This class represents a local variable within a method. It contains its

 * scope, name, signature and index on the method's frame.

 *

 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>

 * @see     LocalVariableTable

 */

public final class LocalVariable

  implements Constants, Cloneable, Node, Serializable

{

  private int start_pc;        // Range in which the variable is valid

  private int length;

  private int name_index;      // Index in constant pool of variable name

  private int signature_index; // Index of variable signature

  private int index;            /* Variable is `index'th local variable on

                                * this method's frame.

                                */

  private ConstantPool constant_pool;

  /**

   * Initialize from another object. Note that both objects use the same

   * references (shallow copy). Use copy() for a physical copy.

   */

  public LocalVariable(LocalVariable c) {

    this(c.getStartPC(), c.getLength(), c.getNameIndex(),

         c.getSignatureIndex(), c.getIndex(), c.getConstantPool());

  }

  /**

   * Construct object from file stream.

   * @param file Input stream

   * @throws IOException

   */

  LocalVariable(DataInputStream file, ConstantPool constant_pool)

       throws IOException

  {

    this(file.readUnsignedShort(), file.readUnsignedShort(),

         file.readUnsignedShort(), file.readUnsignedShort(),

         file.readUnsignedShort(), constant_pool);

  }

  /**

   * @param start_pc Range in which the variable

   * @param length ... is valid

   * @param name_index Index in constant pool of variable name

   * @param signature_index Index of variable's signature

   * @param index Variable is `index'th local variable on the method's frame

   * @param constant_pool Array of constants

   */

  public LocalVariable(int start_pc, int length, int name_index,

                       int signature_index, int index,

                       ConstantPool constant_pool)

  {

    this.start_pc        = start_pc;

    this.length          = length;

    this.name_index      = name_index;

    this.signature_index = signature_index;

    this.index           = index;

    this.constant_pool   = constant_pool;

  }

  /**

   * Called by objects that are traversing the nodes of the tree implicitely

   * defined by the contents of a Java class. I.e., the hierarchy of methods,

   * fields, attributes, etc. spawns a tree of objects.

   *

   * @param v Visitor object

   */

  public void accept(Visitor v) {

    v.visitLocalVariable(this);

  }

  /**

   * Dump local variable to file stream in binary format.

   *

   * @param file Output file stream

   * @throws IOException

   */

  public final void dump(DataOutputStream file) throws IOException

  {

    file.writeShort(start_pc);

    file.writeShort(length);

    file.writeShort(name_index);

    file.writeShort(signature_index);

    file.writeShort(index);

  }

  /**

   * @return Constant pool used by this object.

   */

  public final ConstantPool getConstantPool() { return constant_pool; }

  /**

   * @return Variable is valid within getStartPC() .. getStartPC()+getLength()

   */

  public final int getLength()         { return length; }

  /**

   * @return Variable name.

   */

  public final String getName() {

    ConstantUtf8  c;

    c = (ConstantUtf8)constant_pool.getConstant(name_index, CONSTANT_Utf8);

    return c.getBytes();

  }

  /**

   * @return Index in constant pool of variable name.

   */

  public final int getNameIndex()      { return name_index; }

  /**

   * @return Signature.

   */

  public final String getSignature() {

    ConstantUtf8  c;

    c = (ConstantUtf8)constant_pool.getConstant(signature_index,

                                                CONSTANT_Utf8);

    return c.getBytes();

  }

  /**

   * @return Index in constant pool of variable signature.

   */

  public final int getSignatureIndex() { return signature_index; }

  /**

   * @return index of register where variable is stored

   */

  public final int getIndex()           { return index; }

  /**

   * @return Start of range where he variable is valid

   */

  public final int getStartPC()        { return start_pc; }

  /**

   * @param constant_pool Constant pool to be used for this object.

   */

  public final void setConstantPool(ConstantPool constant_pool) {

    this.constant_pool = constant_pool;

  }

  /**

   * @param length.

   */

  public final void setLength(int length) {

    this.length = length;

  }

  /**

   * @param name_index.

   */

  public final void setNameIndex(int name_index) {

    this.name_index = name_index;

  }

  /**

   * @param signature_index.

   */

  public final void setSignatureIndex(int signature_index) {

    this.signature_index = signature_index;

  }

  /**

   * @param index.

   */

  public final void setIndex(int index) { this.index = index; }

  /**

   * @param start_pc Specify range where the local variable is valid.

   */

  public final void setStartPC(int start_pc) {

    this.start_pc = start_pc;

  }

  /**

   * @return string representation.

   */

  public final String toString() {

    String name = getName(), signature = Utility.signatureToString(getSignature());

    return "LocalVariable(start_pc = " + start_pc + ", length = " + length +

      ", index = " + index + ":" + signature + " " + name + ")";

  }

  /**

   * @return deep copy of this object

   */

  public LocalVariable copy() {

    try {

      return (LocalVariable)clone();

    } catch(CloneNotSupportedException e) {}

    return null;

  }

}