/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

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

import java.io.*;

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

/**

 * IINC - Increment local variable by constant

 *

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

 */

public class IINC extends LocalVariableInstruction {

  private boolean wide;

  private int     c;

  /**

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

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

   */

  IINC() {}

  /**

   * @param n index of local variable

   * @param c increment factor

   */

  public IINC(int n, int c) {

    super(); // Default behaviour of LocalVariableInstruction causes error

    this.opcode = com.sun.org.apache.bcel.internal.Constants.IINC;

    this.length = (short)3;

    setIndex(n);    // May set wide as side effect

    setIncrement(c);

  }

  /**

   * Dump instruction as byte code to stream out.

   * @param out Output stream

   */

  public void dump(DataOutputStream out) throws IOException {

    if(wide) // Need WIDE prefix ?

      out.writeByte(com.sun.org.apache.bcel.internal.Constants.WIDE);

    out.writeByte(opcode);

    if(wide) {

      out.writeShort(n);

      out.writeShort(c);

    } else {

      out.writeByte(n);

      out.writeByte(c);

    }

  }

  private final void setWide() {

    if(wide = ((n > com.sun.org.apache.bcel.internal.Constants.MAX_SHORT) ||

               (Math.abs(c) > Byte.MAX_VALUE)))

      length = 6; // wide byte included

    else

      length = 3;

  }

  /**

   * Read needed data (e.g. index) from file.

   */

  protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException

  {

    this.wide = wide;

    if(wide) {

      length = 6;

      n = bytes.readUnsignedShort();

      c = bytes.readShort();

    } else {

      length = 3;

      n = bytes.readUnsignedByte();

      c = bytes.readByte();

    }

  }

  /**

   * @return mnemonic for instruction

   */

  public String toString(boolean verbose) {

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

  }

  /**

   * Set index of local variable.

   */

  public final void setIndex(int n) {

    if(n < 0)

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

    this.n = n;

    setWide();

  }

  /**

   * @return increment factor

   */

  public final int getIncrement() { return c; }

  /**

   * Set increment factor.

   */

  public final void setIncrement(int c) {

    this.c = c;

    setWide();

  }

  /** @return int type

   */

  public Type getType(ConstantPoolGen cp) {

    return Type.INT;

  }

  /**

   * Call corresponding visitor method(s). The order is:

   * Call visitor methods of implemented interfaces first, then

   * call methods according to the class hierarchy in descending order,

   * i.e., the most specific visitXXX() call comes last.

   *

   * @param v Visitor object

   */

  public void accept(Visitor v) {

    v.visitLocalVariableInstruction(this);

    v.visitIINC(this);

  }

}