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

  2. 

  3. /* ====================================================================

  4.  * The Apache Software License, Version 1.1

  5.  *

  6.  * Copyright (c) 2001 The Apache Software Foundation.  All rights

  7.  * reserved.

  8.  *

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

  10.  * modification, are permitted provided that the following conditions

  11.  * are met:

  12.  *

  13.  * 1. Redistributions of source code must retain the above copyright

  14.  *    notice, this list of conditions and the following disclaimer.

  15.  *

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

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

  18.  *    the documentation and/or other materials provided with the

  19.  *    distribution.

  20.  *

  21.  * 3. The end-user documentation included with the redistribution,

  22.  *    if any, must include the following acknowledgment:

  23.  *       "This product includes software developed by the

  24.  *        Apache Software Foundation (http://www.apache.org/)."

  25.  *    Alternately, this acknowledgment may appear in the software itself,

  26.  *    if and wherever such third-party acknowledgments normally appear.

  27.  *

  28.  * 4. The names "Apache" and "Apache Software Foundation" and

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

  30.  *    derived from this software without prior written permission. For

  31.  *    written permission, please contact apache@apache.org.

  32.  *

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

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

  35.  *    prior written permission of the Apache Software Foundation.

  36.  *

  37.  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

  38.  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

  39.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

  40.  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

  41.  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

  42.  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

  43.  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

  44.  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

  45.  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

  46.  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

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

  48.  * SUCH DAMAGE.

  49.  * ====================================================================

  50.  *

  51.  * This software consists of voluntary contributions made by many

  52.  * individuals on behalf of the Apache Software Foundation.  For more

  53.  * information on the Apache Software Foundation, please see

  54.  * <http://www.apache.org/>.

  55.  */

  56. import java.io.*;

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

  58. 

  59. /** 

  60.  * LDC - Push item from constant pool.

  61.  *

  62.  * <PRE>Stack: ... -> ..., item</PRE>

  63.  *

  64.  * @version $Id: LDC.java,v 1.1.1.1 2001/10/29 20:00:21 jvanzyl Exp $

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

  66.  */

  67. public class LDC extends CPInstruction

  68.   implements PushInstruction, ExceptionThrower, TypedInstruction {

  69.   /**

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

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

  72.    */

  73.   LDC() {}

  74. 

  75.   public LDC(int index) {

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

  77.     setSize();

  78.   }

  79.   

  80.   // Adjust to proper size

  81.   protected final void setSize() {

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

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

  84.       length = 2;

  85.     } else {

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

  87.       length = 3;

  88.     }

  89.   }

  90. 

  91.   /**

  92.    * Dump instruction as byte code to stream out.

  93.    * @param out Output stream

  94.    */

  95.   public void dump(DataOutputStream out) throws IOException {

  96.     out.writeByte(opcode);

  97. 

  98.     if(length == 2)

  99.       out.writeByte(index);

  100.     else // Applies for LDC_W

  101.       out.writeShort(index);

  102.   }

  103. 

  104.   /**

  105.    * Set the index to constant pool and adjust size.

  106.    */

  107.   public final void setIndex(int index) { 

  108.     super.setIndex(index);

  109.     setSize();

  110.   }

  111. 

  112.   /**

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

  114.    */

  115.   protected void initFromFile(ByteSequence bytes, boolean wide)

  116.        throws IOException

  117.   {

  118.     length = 2;

  119.     index  = bytes.readUnsignedByte();

  120.   }

  121. 

  122.   public Object getValue(ConstantPoolGen cpg) {

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

  124. 

  125.     switch(c.getTag()) {

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

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

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

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

  130. 

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

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

  133. 

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

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

  136. 

  137.     default: // Never reached

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

  139.       }

  140.   }

  141. 

  142.   public Type getType(ConstantPoolGen cpg) {

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

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

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

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

  147.     default: // Never reached

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

  149.     }

  150.   }

  151. 

  152.   public Class[] getExceptions() {

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

  154.   }

  155. 

  156.   /**

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

  158.    * Call visitor methods of implemented interfaces first, then

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

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

  161.    *

  162.    * @param v Visitor object

  163.    */

  164.   public void accept(Visitor v) {

  165.     v.visitStackProducer(this);

  166.     v.visitPushInstruction(this);

  167.     v.visitExceptionThrower(this);

  168.     v.visitTypedInstruction(this);

  169.     v.visitCPInstruction(this);

  170.     v.visitLDC(this);

  171.   }

  172. }