    View Javadoc
    1   package org.apache.bcel.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
    58  /***
    59   * GOTO - Branch always (to relative offset, not absolute address)
    60   *
    61   * @version $Id: GOTO.java,v 1.1.1.1 2001/10/29 20:00:13 jvanzyl Exp $
    62   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
    63   */
    64  public class GOTO extends GotoInstruction implements VariableLengthInstruction {
    65    /***
    66     * Empty constructor needed for the Class.newInstance() statement in
    67     * Instruction.readInstruction(). Not to be used otherwise.
    68     */
    69    GOTO() {}
    70
    71    public GOTO(InstructionHandle target) {
    72      super(org.apache.bcel.Constants.GOTO, target);
    73    }
    74
    75    /***
    76     * Dump instruction as byte code to stream out.
    77     * @param out Output stream
    78     */
    79    public void dump(DataOutputStream out) throws IOException {
    80      index = getTargetOffset();
    81      if(opcode == org.apache.bcel.Constants.GOTO)
    82        super.dump(out);
    83      else { // GOTO_W
    84        index = getTargetOffset();
    85        out.writeByte(opcode);
    86        out.writeInt(index);
    87      }
    88    }
    89
    90    /*** Called in pass 2 of InstructionList.setPositions() in order to update
    91     * the branch target, that may shift due to variable length instructions.
    92     */
    93    protected int updatePosition(int offset, int max_offset) {
    94      int i = getTargetOffset(); // Depending on old position value
    95
    96      position += offset; // Position may be shifted by preceding expansions
    97
    98      if(Math.abs(i) >= (32767 - max_offset)) { // to large for short (estimate)
    99        opcode = org.apache.bcel.Constants.GOTO_W;
    100       length = 5;
    101       return 2; // 5 - 3
    102     }
    103
    104     return 0;
    105   }
    106
    107   /***
    108    * Call corresponding visitor method(s). The order is:
    109    * Call visitor methods of implemented interfaces first, then
    110    * call methods according to the class hierarchy in descending order,
    111    * i.e., the most specific visitXXX() call comes last.
    112    *
    113    * @param v Visitor object
    114    */
    115   public void accept(Visitor v) {
    116     v.visitVariableLengthInstruction(this);
    117     v.visitUnconditionalBranch(this);
    118     v.visitBranchInstruction(this);
    119     v.visitGotoInstruction(this);
    120     v.visitGOTO(this);
    121   }
    122 }

This page was automatically generated by Maven