/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

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

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

 * 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.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    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 apache@apache.org.

 *

 * 5. Products derived from this software may not be called "Apache",

 *    "Apache BCEL", nor may "Apache" appear in their name, without

 *    prior written permission of the Apache Software Foundation.

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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * ====================================================================

 *

 * 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.*;

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

/**

 * LDC - Push item from constant pool.

 *

 * <PRE>Stack: ... -&gt; ..., item</PRE>

 *

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

 */

public class LDC extends CPInstruction

  implements PushInstruction, ExceptionThrower, TypedInstruction {

  /**

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

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

   */

  LDC() {}

  public LDC(int index) {

    super(com.sun.org.apache.bcel.internal.Constants.LDC_W, index);

    setSize();

  }

  // Adjust to proper size

  protected final void setSize() {

    if(index <= com.sun.org.apache.bcel.internal.Constants.MAX_BYTE) { // Fits in one byte?

      opcode = com.sun.org.apache.bcel.internal.Constants.LDC;

      length = 2;

    } else {

      opcode = com.sun.org.apache.bcel.internal.Constants.LDC_W;

      length = 3;

    }

  }

  /**

   * Dump instruction as byte code to stream out.

   * @param out Output stream

   */

  public void dump(DataOutputStream out) throws IOException {

    out.writeByte(opcode);

    if(length == 2)

      out.writeByte(index);

    else // Applies for LDC_W

      out.writeShort(index);

  }

  /**

   * Set the index to constant pool and adjust size.

   */

  public final void setIndex(int index) {

    super.setIndex(index);

    setSize();

  }

  /**

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

   */

  protected void initFromFile(ByteSequence bytes, boolean wide)

       throws IOException

  {

    length = 2;

    index  = bytes.readUnsignedByte();

  }

  public Object getValue(ConstantPoolGen cpg) {

    com.sun.org.apache.bcel.internal.classfile.Constant c = cpg.getConstantPool().getConstant(index);

    switch(c.getTag()) {

      case com.sun.org.apache.bcel.internal.Constants.CONSTANT_String:

        int i = ((com.sun.org.apache.bcel.internal.classfile.ConstantString)c).getStringIndex();

        c = cpg.getConstantPool().getConstant(i);

        return ((com.sun.org.apache.bcel.internal.classfile.ConstantUtf8)c).getBytes();

    case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Float:

        return new Float(((com.sun.org.apache.bcel.internal.classfile.ConstantFloat)c).getBytes());

    case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Integer:

        return new Integer(((com.sun.org.apache.bcel.internal.classfile.ConstantInteger)c).getBytes());

    default: // Never reached

      throw new RuntimeException("Unknown or invalid constant type at " + index);

      }

  }

  public Type getType(ConstantPoolGen cpg) {

    switch(cpg.getConstantPool().getConstant(index).getTag()) {

    case com.sun.org.apache.bcel.internal.Constants.CONSTANT_String:  return Type.STRING;

    case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Float:   return Type.FLOAT;

    case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Integer: return Type.INT;

    default: // Never reached

      throw new RuntimeException("Unknown or invalid constant type at " + index);

    }

  }

  public Class[] getExceptions() {

    return com.sun.org.apache.bcel.internal.ExceptionConstants.EXCS_STRING_RESOLUTION;

  }

  /**

   * 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.visitStackProducer(this);

    v.visitPushInstruction(this);

    v.visitExceptionThrower(this);

    v.visitTypedInstruction(this);

    v.visitCPInstruction(this);

    v.visitLDC(this);

  }

}