/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

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

/* ====================================================================

 * The Apache Software License, Version 1.1

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 * reserved.

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 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

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 *    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.

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 *    "Apache BCEL" must not be used to endorse or promote products

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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

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 */

import java.io.*;

import com.sun.org.apache.bcel.internal.util.ByteSequence;

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

import com.sun.org.apache.bcel.internal.classfile.*;

/**

 * Abstract super class for instructions that use an index into the

 * constant pool such as LDC, INVOKEVIRTUAL, etc.

 *

 * @see ConstantPoolGen

 * @see LDC

 * @see INVOKEVIRTUAL

 *

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

 */

public abstract class CPInstruction extends Instruction

  implements TypedInstruction, IndexedInstruction

{

  protected int index; // index to constant pool

  /**

   * Empty constructor needed for the Class.newInstance() statement in

   * Instruction.readInstruction(). Not to be used otherwise.

   */

  CPInstruction() {}

  /**

   * @param index to constant pool

   */

  protected CPInstruction(short opcode, int index) {

    super(opcode, (short)3);

    setIndex(index);

  }

  /**

   * Dump instruction as byte code to stream out.

   * @param out Output stream

   */

  public void dump(DataOutputStream out) throws IOException {

    out.writeByte(opcode);

    out.writeShort(index);

  }

  /**

   * Long output format:

   *

   * <name of opcode> "["<opcode number>"]"

   * "("<length of instruction>")" "<"< constant pool index>">"

   *

   * @param verbose long/short format switch

   * @return mnemonic for instruction

   */

  public String toString(boolean verbose) {

    return super.toString(verbose) + " " + index;

  }

  /**

   * @return mnemonic for instruction with symbolic references resolved

   */

  public String toString(ConstantPool cp) {

    Constant c   = cp.getConstant(index);

    String   str = cp.constantToString(c);

    if(c instanceof ConstantClass)

      str = str.replace('.', '/');

    return com.sun.org.apache.bcel.internal.Constants.OPCODE_NAMES[opcode] + " " + str;

  }

  /**

   * Read needed data (i.e., index) from file.

   * @param bytes input stream

   * @param wide wide prefix?

   */

  protected void initFromFile(ByteSequence bytes, boolean wide)

       throws IOException

  {

    setIndex(bytes.readUnsignedShort());

    length = 3;

  }

  /**

   * @return index in constant pool referred by this instruction.

   */

  public final int getIndex() { return index; }

  /**

   * Set the index to constant pool.

   * @param index in  constant pool.

   */

  public void setIndex(int index) {

    if(index < 0)

      throw new ClassGenException("Negative index value: " + index);

    this.index = index;

  }

  /** @return type related with this instruction.

   */

  public Type getType(ConstantPoolGen cpg) {

    ConstantPool cp   = cpg.getConstantPool();

    String       name = cp.getConstantString(index, com.sun.org.apache.bcel.internal.Constants.CONSTANT_Class);

    if(!name.startsWith("["))

      name = "L" + name + ";";

    return Type.getType(name);

  }

}